Patent US3594589A successfully refreshed from Google Patents.
US3594589A
Expired / Lapsed
US
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Sample and hold circuit
Assignee: Massachusetts Institute of Technology
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Filing: 1970-03-23
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Granted: 1971-07-20
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Expires: 1990-03-23
Abstract
Abstract A circuit for maintaining the level of an output signal at a value which is essentially equal to the value of a periodically sampled input signal, said circuit including a pair of gates which are made simultaneously conductive over a controlled sampling time interval whereby an input signal is applied to a storage device which thereupon produces an output signal, the level of which is maintained for a particular time period at the level of the sampled input signal.
Inventors
- 👤 Robert L Hall
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:14
CPC Classifications
G; G11; G11C; G11C27/00; G11C27/02; G11C27/024
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
269 words
Sample and hold circuitry for providing an output signal in response to an input signal applied thereto during an interval of time and for maintaining the value of said output signal at substantially the value of said input signal for a prescribed period of time beyond said interval of time, said sample and hold circuitry comprising: a. storage means responsive to said input signal for providing said output signal; b. means for producing a first control signal; c. first gating means coupled to said input signal and to said first control signal, said first gating means being adapted to conduct while said first control signal remains less than a predetermined threshold value, said predetermined threshold value being greater than zero and at a first polarity, and to cease conducting when said first control signal becomes greater in value than said predetermined value at said first polarity; d. means responsive to said first control signal for amplifying and changing the polarity of said first control signal, thereby producing a second control signal of a polarity continually opposite to the polarity of said first control signal; and e. second gating means coupled to said first gating means and to said second control signal, said second gating means being adapted to conduct while said second control signal remains less than said predetermined threshold value and to cease conducting when said second control signal becomes greater in value than said predetermined threshold value, such that said first gating means and said second gating means are simultaneously conductive for said interval of time during which said input signal is applied to said storage means.
Claim 2
Dependent Claim
269 words
Sample and hold circuitry for providing an output signal in response to an input signal applied thereto during an interval of time and for maintaining the value of said output signal at substantially the value of said input signal for a prescribed period of time beyond said interval of time, said sample and hold circuitry comprising: a. storage means responsive to said input signal for providing said output signal; b. means for producing a first control signal; c. first gating means coupled to said input signal and to said first control signal, said first gating means being adapted to conduct while said first control signal remains less than a predetermined threshold value, said predetermined threshold value being greater than zero and at a first polarity, and to cease conducting when said first control signal becomes greater in value than said predetermined value at said first polarity; d. means responsive to said first control signal for amplifying and changing the polarity of said first control signal, thereby producing a second control signal of a polarity continually opposite to the polarity of said first control signal; and e. second gating means coupled to said first gating means and to said second control signal, said second gating means being adapted to conduct while said second control signal remains less than said predetermined threshold value and to cease conducting when said second control signal becomes greater in value than said predetermined threshold value, such that said first gating means and said second gating means are simultaneously conductive for said interval of time during which said input signal is applied to said storage means.
Claim 3
Dependent Claim
50 words
The sample and hold circuitry of claim 1 wherein said means for producing said second control signal comprises an amplifier, and wherein the duration of said interval of time during which said first and second gating means are simultaneously conductive by being substantially determined by the gain of said amplifier.
Claim 4
Dependent Claim
70 words
The sample and hold circuitry of claim 1 wherein said storage means is a capacitor, said input signal thereby being applied to said capacitor for said interval of time to allow said capacitor to charge up to the value of said input signal, said capacitor thereafter maintaining said charge substantially at said value for a prescribed period of time after said input signal is no longer applied to said capacitor.
Claim 5
Dependent Claim
42 words
The sample and hold circuitry of claim 1 wherein said first and said second gating means each comprise a P-channel junction field effect transistor, said predetermined value is the pinch-off voltage of said transistors, and further wherein said first polarity is positive.
Claim 6
Dependent Claim
42 words
The sample and hold circuitry of claim 1 wherein said first and said second gating means each comprise an N-channel junction field effect transistor, said predetermined value is the pinch-off voltage of said transistors, and further wherein said first polarity is negative.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-07-19 | 1975-01-18 | 1975-07-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-07-19 | 1979-01-18 | 1979-07-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-07-19 | 1983-01-18 | 1983-07-20 | $7700.00 | Window Closed / Lapsed |